Electrical therapeutic apparatus and method



2 Sheets-Sheet 1 1NVENTOR$ ATTORNEY.

Filed April 28, 1936 Dec. 3, 1940. A. D. CARDWELL; ElAL ELECTRICAL THERAPEUTIC AlPARATUS AND METHOD Dec. 3,1940. CARDWEFL ErAL' 2223,35)

ELECTRICAL THERAPEUTIC APPARATUS AND METHOD Filed April 28, 1936 2 Sheets-Sheet 2 as as j 9 FIGQS 1N VENT OR-S ATTORNEY.

Patented Dec. 3, 1940 PATENT OFFICE 2,223,350 ELECTRICAL THERAPEUTIC APPARATUS AND METRO Allen D. Cardwell, Rockville iUentre,

and Ralph R. Batcher, St. Albans, N. Y., assignors to Allen D. Cardwell Manufacturing Corporation, a corporation of N ew York Application April 28, 1936, Serial No. 76,720

16 Claims.

This invention relates to electro-therapeutic apparatus. v

An object of the invention is to provide a means for readily, safely and without particular skill on the part of the operator, applying electric energy for the treatment of conditions in the body which are to be relieved.

A further object of the invention is to provide means whereby desired changes in the characteristics of the energy supplied, such as fre quency and/or power etc., may be effected by interchanging units each of which comprises the combination of circuit elements necessary to produce the desired conditions.

A further object of the invention is to provide a simple and readily usable means for providing different frequencies of alternating current for the part of the body afiected or for the treatment of different affections.

A further object of the invention is to provide a means whereby the frequency of the applied current is quickly and accurately changed by means of interchangeable control units which may be readilyinserted into or removed from the apparatus.

A further object of the invention is to provide, in connection with the interchangeable frequency control units, other elements carried by the control units by which other circuit functions, as for example power out-put, may be altered simultaneously with the interchanging of the units.

A further object of the invention is to provide apparatus of the character described wherein variation in the length, location or size of the leads from the apparatus to the patient will not introduce material changes in the power delivered to thepatient or in the predetermined frequency thereof. A further object of the invention is to provide means of the character as indicated which will permit of any applicators desired being used such as cutting devices, devices for coagulating, heating pads etc., all of such devices being intended to be included in the appended claims under the term applicator.

Other and ancillary objects of the invention will appear hereinafter.

In the accompanying drawings which illustrate the invention- Fig. Us a top plan view ing the invention;

Fig.- 2 is a section on the line 2-2 of Fig. 1:

Fig. 3 is an end view looking from the righthand end of Figs. 1 and 2;

of apparatus embody- Fig. 4 is a wiring diagram of the electrical connections; Fig. 5 is a top plan view, partly broken away,

of a modified form of unit comprising removable coil and other circuit altering elements; 5

Fig. 6 is a view similar to Fig. 5 but with a different circuit altering element; and

Fig. 7 is a view similar to Fig. 5 of a still further modification.

Referring to the drawings and first to Figs. 1 10 to 4 inclusive, the apparatus comprises two transformers P and F, one having its primary I connected through conductor: 2 with one side of a suitable alternating current source of supply of suitable frequency as for instance 60 cycles, while the other terminal of the primary I is connected through the conductor 3 and leg of the double-pole switch 4 with the other terminal of the source of supply; and the other transformer F having one terminal of its primary 5 connected through a conductor 6 and the conductor 2 with one side of the source of supply, while the other terminal of the primary is connected through the conductor 1 and the other leg of the switch 4 with the other side of the source of supply.

The first mentioned transformer P is for energizing the plate circuits, while the other F is for energizing the filament circuits of the thermionic vacuum tubes i2 and i3 which are employed as oscillators to give the desired high frequencies. It will be observed that the primaries of these transformers l and 5 arethus connected in parallel across the source of supply when the switch 4 is closed, and when the switch a is opened all power is removed from both transformers. The secondary 8 of the transformer F has one of its terminals connected through the conductor 9 with one terminal of each of the filaments I0 and H of the oscillating tubes [2 and I3 as above 40 referred to, and the other terminal of the sec ondary 8 is connected through the conductor M with the other terminals of the filaments land H so that the filaments l0 and H are connected in parallel across the transformer secondary 8.

The midpoint of the secondary 8 is connected through a conductor l5 and milliammeter I6 with one terminal of the transformer secondary ll, the otherend of which secondary is connected by a conductor ill with a plug contact IS. A tap 20 connects from an intermediate point of the secondary H with the stationary plug contact 2! so that when the connection is made through !9 a greater voltage will be impressed upon the cir- .4: hav

cuit by the transformer secondary l 7 than is the case when connection is made through the contact 2|.

with the arrangement shown in the wiring diagram of Fig. 4, a removable coil 22 has its terminals connected with the plug contacts 22 and-24 adapted to be plugged into the stationary contacts 25 and 26 which are respectively connected with the plates 21 and 28 of the vacuum tubes, and as the contacts 23 and 24 are plugged into the contacts 25 and 26, the contact22 will be plugged into the contact 2| whereby an intermediate point of thecoil 22 will be connected through the conductor 20 with an intermediate point of the transformer.

The plate circuits of the vacuum tubes will now appear as follows; The circuit is traced from the filaments iii and H of the vacuum tubes through the conductors 9 and H to the terminals of the secondary 8 of the filament energizing transformer F, thence through the conductor i5 connected with the mid-point of the secondary 8, through the milliameter i6 and the secondary l'l of the transformer P, thence through the conductor 20 to contacts 2| and 29 to the mid-point of the coil 22 whence the circuit branches in opposite directions, one branch passing through the contacts 25 and 22 to the plate .21 of the tube i2 and the other branch passing through the contacts 24 and 2G to the plate 28 of the tube l2.

The grids 20 and 2| of the vacuum tubes are connected together through the inductance coil 32. The midpoint of coil 22 is connected through the high non-inductive resistance 22 and the conductor IS with the midpoint of the transformer secondary '2 to provide a grid leak.

The grid circuit is excited by grid coil 22.

It may be desirable to provide different excitation at different operating frequencies to obtain optimum operating emciency. This is accomplished by providing a grid circuit that islarge enough to permit efflclent operation on the lower frequencies to be used and then, if desired to reduce the excitation at any higher frequency, reducing the inductance of the coil by short circuiting a portion of the coil so as to alter its effect upon the circuit. Thus a tap 24 from an intermediate point of the coil 22 is connected with the stationary contact 25, while a tap 22 from a point of the coil which is at the same distance from itsadjacent end of the coil as is the tap 24 from its adjacent coil end, is connected with the contact 21, while upon the removable unit carrying the coil 22 are the contacts 22 and 29 connected by the short-circuiting conductor 40, contacts 28 and 22 being adapted to be respectively plugged into the contacts 25 and 21 whenthe unit carylng the coil 22 and the contacts 22, 22, 22, 22 and 24 is placed in position, the contacts 22, .22, 22, 22 and 24 being respectively and simultaneously plu edinto the stationary contacts 25, 22, 2|, 2! and 22. Or, a

certain portion of the grid coil 22 may be shunted with an inductance as in Fig. 8. Or, similar results may be accomplished by using a grid coil smaller than that for the lower frequencies and to shunt all or a portion of it with a condenser '22 as in Fig. 5, when such low; frequency output coils are being used.

4H,, Adjustablycouplcd with the coil 22 is an outterminallof which are con-' p t-coil 4| to .nected the leads 42and 42 leading to the applicaters 44 and 42 which may consist of conductors enclosed in rubber pads, cutting imassasso plements or any means by which the energy is applied to the part desired. v

While the applicator leads 42 and 43 are shown as connected to the extremities of the coil 4|, such coil might be provided with any 5 desired number of intermediate taps 14 located at different points along the coil to which a lead 42 or G2 could be selectively connected thereby including such portion of the coil as is desired between the leads.

The mechanical arrangement of the apparatus may be as shown in Figs. 1, 2 and 3 wherein upon the base 46 are mounted the transformers P and F. .Also mounted upon the base are the vacuum tubes i2 and I2 having their axes vertical and the grid coil 22 with its axis horizontal. Also upon the base is mounted a frame or support 41 of wood or. other suitable insulating material upon an insulating strip on which are mounted the contacts 25, 25, i2, 2|, 3i and 26.

Sliding upon the guides 48 is a carrier 49 of porcelain or other suitable insulating material comprising the handle portion 50, and in the hole 22 of which is mounted the inductance coil 22 having its terminals connected with the contacts 22 and 24 as before described, these contacts 22 and 24 and also the contacts 28, 29 and 22 being mounted upon the porcelain carrier whereby they are suitably insulated from each other and adapted to plug into .the' contacts 25,-30

25, 2|, 21 and 22 when the por celain carrier or frame with its carried inductance coil are inserted into position in the frame. The coil 4| is fixed on a shaft ii rotatably mounted on the support 41 and provided with a-knob 52 by which 35 it may be turned. The output coil 4| may thus be turned into its extreme uncoupled position as shown in Figs. 1, 2 and 3 or, by turning the shaft 5|, the coil 4| may be moved down within the coil 22 to any desired extent.

When the carrier 42 carrying the coil 22 has been inserted in positionupon the frame and the contacts engaged as described, and the shaft it has been turned to turn the coil 4| downwardly to an operative position within the coil 22, the 45 round-ended projection 54 fixed upon the shaft will have come into engagement with the spring latch 52 secured at one end to the support 41 which will thus be pushed downwardly so as to latch back of the carrier 42 and prevent the re- 50 moval of the carrier 42. When, however, it 1s desired to interchange the carrier, the shaft ii is turned to elevate the coil 4| into the position as shown in Fig. 2,.when the latch 55 will be released from the projection 54 and will spring up (see Fig. 2) so as to permit the carrier 49 to be slid out of the support. It will thus be seen that it is impossible to remove the carrier 49, which involves the breaking of connection with the coil 22 and other carried apparatus. while 60 the output coil 4| is in operative relation to the coil 22, but that the output coil must be moved into uncoupled relation before the carrier can be removed.

To automatically disconnect the supply circuit 65 when a carrier 42 is removed and to close such circuit when the carrier is placed in cperative position, normally open spring-contacts 1e are inserted in the supply line 2. Thesecontacts are. adapted to-be closedwhen a plunger Ii is inserted between them. The plunger reciprocates in a cylinder 12 mounted on the support 41 and tends to be retracted out of connecting position 'byaspring'll. Whe'n'acarrierti's inserted into tive position it abuts against the end of the plunger and pushes it against the pres sure of the spring so that it engages and connects the contacts 10 and conversely, when the carrier is withdrawn the spring retracts the plunger and opens connection between the conacts.

The various parts of the circuits are so proportioned and arranged that the desired high frequency is applied to the applicators and the energy applied is regulated by the turning of the shaft by the knob 52 whereby the coupling of the output coil 4| with the coil 22 is varied at the will of the operator. It is advocated, however, that different frequencies be used fordifferent ailments, and to this end there may be a plurality of carriers as 49 having coils 22 of different numbers of turns, and therefore of difierent inductance, respectively, or coils shunted with various capacities, and these coils may be interchanged in the apparatus by removing a carrier 49 carrying one coil 22 and inserting an other carrier carrying a. coil having a diiferent number of turns or shunted by a different capacity. By thus interchanging the coils the frequency of the voltage in the output to the applicators is altered and this alteration may be such as to suit the treatment in hand. The interchange of the coils 22 as described to obtain the desired frequencies by the insertion and removal of the carrier which also automatically effects the necessary connections, provides a simple means whereby even a person unskilled in electricity may effect the proper adjustments. It may not even be necessary for the physician or other operator to know at what frequency he is working. It has been quite definitely established in relation to certain ailments that a certain frequency is required and a carrier t9 carrying a suitable coil 22 and other equipment giving that frequency may be labeled with the name of the ailment, so that in making a treatment the operator simply inserts into the support 4? the carrier t9 which is labeled with the ailment to be treated when the proper conditions will be realized with small knowledge on the part of the operator of the nature of the electrical actions involved.

The output circuit, including the applicators and the coil 4!, may be attuned to resonance if desired and the applicators located'at potential nodes. It has been found when this is done that the length, size and position of the leads must be definitely fixed. With the arrangement shown the length of leads from the output coil to the applicators may be varied anywhere from three to six feet or more without introducing changes in the power delivered even though the portion of the body of the patient in the field is relatively short with respect to the lengths of the leads, by using a coupling coil with a relatively large number of turns whereby a large voltage can be induced even though the circuit is not resonance. The use of a non-resonant circuit as described, eliminates the need for leads of fixed definite lengths. Variation in the load requirement due to the application of the pads at different positions, changes in the area and spacing of the pads, and necessary changes in the power requirements due to the nature of the treatment, all can be compensated for by altering the cou pling between the plate circuit coil and the output circuit coil. It is to be noted that the output circuit is electrically insulated from the high voltage circuit which eliminates the danger of the operator or the patient receiving electrical shocks.

It is found that each frequency requires the changes of certain circuit constants. According to the present invention all these changes necessary to produce the desired result are produced by insertion of a single unit whereby the care and skill required of the operator is reduced to a minimum; for instance, it may be that some of the coils 22 inserted in the apparatus may change the circuit constants so as to require a corresponding change in the constants of the grid circuit; thus, a coil 22 may be such that instead of the short circuiting conductor 40a suitable capacity be connected across the portion of the coil 32 to produce the desired conditions. Accordingly a condenser 56 mounted upon the carrier 49 may have its terminals connected with the contacts 38 and 39, so that upon inserting the carrier in operative position the condenser (in place of the short-circuiting conductor 40) will be connected by the conductors 34 and 36 across the portion of the grid coil 32, the other connections established being as described.

In some instances the desired conditions might be realized in connection with the output coil carried by the carrier 49 by connecting an inductance 51 across a portion of the coil 32 by the conductors 34 and 36. Accordingly an inductance coil 51 is mounted upon the carrien 49 and has its terminals connected with the contacts 38 and 39 in place of the short-circuiting conductor 40, the other connections being as before described.

In still other circumstances it may be desirable to change the effective amount of the resistance 33 in circuit, and to this end two additional con tacts 58 and 59 are mounted upon the carrier 49 with corresponding stationary plug contacts 60 and iii, the contact 6! being connected by conductor 62 with an intermediate point of the resistance 33 while the contact 6| is connected by a conductor $3 with an end of the resistance 33. The contacts 58 and 59 are connected by a short circuit conductor 56 mounted on the carrier 49 so that when the carrier 49 is placed in position the portion of the resistance 33 between the points of connection of the conductors 62 and 93 is short circuited and thereby cut out of action to effect the desired relationships.

It is to be observed that in Fig. 4 the center point of the coil 22 is connected through the tap 20 with an intermediate point of the transformer secondary IT, whereby less than the whole secondary voltage is applied, As it is desirable to increase the plate voltage at some of the lower frequencies or with certain applications, this can be accomplished, in. carriers having a coil 22 for such lower frequencies, by connecting the intermediate point of that coil with the contact 65 (as indicated in dotted lines in Fig. 4) instead of with the contact 29, when the connection will be established through the contact i9 and conductor 18 with the end of the secondary l1, so that the voltage impressed will be increased over that where the connection is made to the intermediate point of the transformer secondary H by the con- What we claim is:

1. In electro-therapeutic apparatus, the combination with a circuit including an oscillator and a coil adapted to be connected and disconnected in the circuit to control the frequency of the current applied to a patient, of an output coil inductively coupled with the first mentioned coil and movable with relation thereto to control the coupling therebetween and an applicator connected with said output coil, said output coil being movable into and out of the first mentioned coil when the latter is in operative position whereby the first mentioned coil is prevented from disconnection while the said output coil is in position to be within the first mentioned coil.

2. In electro-therapeutic apparatus, the combination with a circuit including an oscillator and a coil adapted to be connected and disconnected in the circuit to control the frequency of the current applied to a patient, of an output coil inductively coupled with the first mentioned coil and movable with relation thereto to control the coupling therebetween and an applicator connected with said output coil, the output circuit being non-resonant with relation to the first mentioned circuit, said output coil being movable into and out of the first mentioned coil when the latter is in operative position whereby the first mentioned coil is prevented from disconnection while the said output coil is in position to be within the first mentioned coil.

3. In electro-therapeutic apparatus, the combination with a circuit including an oscillator and having contacts connected thereto and a unitary member having a coil adapted to control the frequency of the current applied to'a patient and connected with contacts on said unitary member adapted to engage with the first mentioned contacts when the said unitary member is placed in position, of a movableoutput coil inductively coupled with the first mentioned coil when the-said unitary member is in connected position, to control the coupling between the said coils and an applicator connected with saidoutput coil, said output coil being movable into and out of the first mentioned coil when the latter is in operative position whereby the first mentioned coil is prevented from disconnection while the said output coil is in position to be within the first mentioned coil.

4. In electro-therapeutic apparatus, the combination with a circuit including an oscillator and having contacts connected thereto and a unitarymember having a coil adapted to control the freuency of the current applied to a patient and connected with contacts on said unitary member adapted to engage with the first mentioned contacts when the said unitary member is placed in position, of an output coil inductively coupled to the first mentioned coil when the said unitary member is in, connected position, to control the coupling between the said coils and an applicator connected with said output coil and an element for alteringa constant of the first mentioned circuit, said element being mounted on said unitary member, contacts on said unitary member to which said element is connected and stationary contacts connected with .the last mentioned circuit and adapted to be engaged by the contacts connected with said element when said unitary member is placed in position and disengaged therefrom when said unitary member is removed from 0D- erating position.

5. In electro-therapeutlc, apparatus, the corn= 6. In electro-therapeutic apparatus, the com- I bination with a circuit including an oscillator and a coil movable into and out of operative relation to said circuit and an output coil inductively coupled with the first mentioned coil and movable with relation thereto to control the coupling therebetween and an applicator connected with said output coil, of means controlled by the position of said output coil for controlling the removal of said first mentioned coil from operative position.

7. In electro-therapeutlc apparatus, the combination with a circuit including an oscillator and having contacts connected thereto and a unitary member movable into and out of operative position and having a coil adapted to control the frequency of the current applied to a patient and connected with contacts on said unitary member, said contacts being adapted to engage. with the first mentioned contacts when the said unitary member is placed in position, of an output coil inductively coupled with the first mentioned coll when the said unitary member is in operative position, an applicator connected with said output coil and means controlled by the position of said output coil with relation to the first mentioned coil for preventing the removal of said unitary member from operative position 8. In electro-therapeutic apparatus, the combination with a circuit including a thermionic vacuum tube oscillator and a grid circuit and having contacts connected thereto and a unitary member having a coil adapted to control the frequency of the current applied to a patient and connected with contacts on said unitary member adapted to engage with the first mentioned contacts when the said untary member is placed in position, of an output coil inductively coupled to the first mentioned coil when the said unitary member is in operative position and movable to control the coupling between the said coils, an applicator connected with said output coil and an element for altering a constant of the said 'grid circuit, said element being mounted on said unitary member, contacts on said unitary member to which said element is connected and stationary contactsconnected with the said grid circuit and adapted to be engaged by the contacts connected with said element when said unitar'y member is placed in position and disengaged therefrom when said unitary member is removed from operating position.

9. In electro-therapeutic apparatus, the combination with a circuit including a thermionic vacuum tube oscillator having a plate circuit,

7 position to control the coupling between the said coil and an applicator connected with said output coil, said output coil being movable into and out of the first mentioned coil when the latter is in operative position whereby the first mentioned coil is prevented from disconnection while the said output coil is in position to be within the first mentioned coil.

10. In electro-therapeutic apparatus, the combination with a. circuit including an oscillator having plate and grid circuits, contacts connected thereto and a unitary member having a coil adapted to control the frequency of the current applied to a patient and connected with contacts on said unitary member adapted to engage with contacts connected with said plate circuit when the said unitary member is placed in operative position, of an output coil inductively coupled to the first mentioned coil when the said unitary member is in operative position and movable to control the coupling between the said coils and an applicator connected with said ,putput coil and an element for altering a constant of the said grid circuit, said element being mounted on said unitary member, and contacts on said unitary member to which said element is connected and adapted to be engaged by contacts connected with said grid circuit when said unitary member is placed in position.

11. In electro-therapeutic apparatus, the

35 -bination with a circuit including an oscillator and aunit comprising a coil adapted to be con nected and disconnected in the circuit, to control the frequency of the current applied to a patient. of an output coil inductively coupled with the first mentioned coil and movable with relation thereto to control the coupling therebetween and an applicator connected with said output coil, 9. supply circuit and means controlled by said unit for controlling said supply circuit.

12. In electro-therapeutic apparatus, the combination with a circuit including an oscillator, of a selected master control unit connectible and disconnectible in the said circuit, said unit determining the frequency appied to a patient and other circuit elements and contacts carried by said unit for controlling conditions in the oscillator circuit whereby such conditions are kept at optimum efl'ectiveness for that frequency.

13. The method of varying the frequency of electric energy applied in therapeutic treatment, which energy is derived from a circuit containing an oscillator and an application circuit in,-

ductively coupled with the aforesaid circuit, which consists in interchanging coupling coil units in the first mentioned circuit applying the energy of said application circuit to apatient and varying the voltage of the said application circuit by varying the inductive coupling between said application circuit and the said circuit containing an oscillator.

14. The method of varying the electric energy applied in therapeutic treatment, which energy is derived from a circuit containing an oscillator and an application circuit inductively coupled with the aforesaid circuit, which consists in disconnecting a coupling coil unit from the first mentioned circuit and connecting another coupling coil unit in the first mentioned circuit in place of the disconnected coil unit, applying the energy of said application circuit to a patient and varying the voltage of the said application circuit by varying the inductive coupling between said application circuit and the said circuit containing an. oscillator.

15. The method of varying the characteristics of electric energy applied in therapeutic treatment, which energy is derived from a circuit containing an oscillator, which method consists in interchanging frequency determining units in said circuit by disconnecting a frequency-determining unit from said circuit and connecting another frequency-determining unit to said circult in place of the disconnected unit, applying the energy of said application circuit to a patient and varying the voltage of the said application circuit by varying the inductive coupling between said application circuit and the said circuit containing an oscillator.

16. In electro-therapeutlc apparatus, the combination with a circuit including an oscillator and a unit comprising a coil adapted to be connected and disconnected in the circuit, to control the frequency of the current applied to a patient, of an output coil inductivetly coupled with the first mentioned coil and movable with relation thereto to control the coupling therebetween, an 

